This invention relates to a process for durably modifying a fibrous substrate with a polyoxyethylene-containing silane and to a modified fibrous substrate obtained therefrom.
Many fibrous substrates possess some degree of hydrophobicity because they comprise a hydrophobic fiber and/or because they bear hydrophobic surface-modifying agents such as sizes, dyes, crease-resistant resins, softening agents, flame retardants and binders. While being desirable in some fibrous substrates, hydrophobicity in others, such as textiles, other than in rainwear, is undesirable and is believed to be responsible for such well-known problems as the lack of "cotton-comfort" and poor oil-borne soil-release during laundering of the textile.
It is known that the hydrophilicity and soil-release properties of synthetic fabrics may be improved by applying hydrophilic polymers thereto. In particular, Pittman et al., U.S. Pat. No. 3,639,156, teaches that a fibrous substrate may be modified with a siloxane homopolymer which contains recurring units of the structure YO(Alk-O).sub.b XSiG.sub.c O.sub.d /2, such as CH.sub.3 O(CH.sub.2 CH.sub.2 O).sub.12 CH.sub.2 CH.sub.2 CH.sub.2 SiO.sub.3/2.
However, when one treats a textile with an aqueous solution of hydrolyzed ##STR1## and heats the treated textile to cure the siloxane, the resulting treatment is not durable to laundering. It is thought that this non-durability to laundering is due to the known reluctance of the polyoxyethylene-substituted silane precursor to adequately condense, i.e. cure, to a siloxane structure when there is more than three oxyethylene units in the polyoxyethylene substituent and said substituent is bonded to silicon through a propyleneoxy group, as demonstrated by Birchall, et al., Nature, Vol. 266, p. 154 (10 March 1977).